Summary At about 0220 EDT on 23 September 1994, the self-unloading bulk carrier ALGOLAKE was transiting the St. Lawrence River bound for Detroit, USA, with a load of iron ore. The vessel was making approximately 8.5 knots over the ground. A few seconds after passing at a distance of approximately 23 metres from buoy K108, the vessel vibrated for a few minutes and then ran aground approximately one half-mile upstream from buoy K108. The ALGOLAKE sustained damage to the hull, but there were no injuries or pollution reported as a result of this occurrence. Ce rapport est galement disponible en franais. Factual Information At about 0155(1) on 23 September 1994, the pilot of the ALGOLAKE came to an agreement with the pilot of the vessel GREAT LAKER, also bound for the St. Lawrence Seaway, to arrange for a safe overtaking situation. The agreement was to let the GREAT LAKER pass in the south part of the channel while the ALGOLAKE would follow the northern limit of the channel. The overtaking proceeded without incident at about 0220. At the time, the ALGOLAKE was abreast of buoy K108, at a reported distance of approximately 23 m. The pilot then ordered a course of 210(G), and a few seconds later he ordered a course of 213(G). At that point, the vessel began vibrating abnormally. The course ordered did not change even when the quartermaster put the wheel 20 to starboard and then hard-a-starboard. The engine was stopped, and a few minutes later the vessel struck the northern limit of the channel, sheered some 3 to port, and then came to a standstill. Subsequent soundings indicated that the vessel was in contact with the bottom on the starboard side forward of the accommodation. Various notices had been broadcast since 20 July 1994 to the effect that some buoys, including buoy K108, had been temporarily displaced 45 m outside the channel for dredging operations. Written notices had been sent to the Laurentian Pilotage Authority. Hydrographic soundings taken on the day of the occurrence recorded a depth of water greater than 12.9 m in the channel in the area of the grounding. The soundings also indicated that the depth of water was less than the vessel's draught, given the state of the tide at the time of the occurrence, some 20 m north of the channel.